Health services research currently lacks a consistent definition of a “high performing” health care delivery system despite an increased emphasis by health care purchasers, payers and policymakers on measuring and rewarding such systems, according to an AHRQ-funded systematic literature review. Without a consistent definition, the review authors indicated, it is less meaningful to compare the performance of different systems and severely limits the ability to develop a general policy, or reward system, for achieving high performance. Although all definitions found in the literature review used one or more attributes to define high performance, only five studies used five or more attributes. Of the attributes used most often – quality, cost, access, equity, patient experience and safety – quality and cost were most commonly paired. This research was funded by AHRQ’s Comparative Health System Performance Initiative, which studies how health care delivery systems promote evidence-based practices and patient-centered outcomes research in delivering care. Access the abstract, published July 10 in the Joint Commission Journal on Quality and Patient Safety.